The statement, posted to social media, follows weeks of speculation about Al-Qahtani’s fate, including rumours of his arrest.
Al-Qahtani, whose real name is Muyassar ibn Ali al-Juburi, was born in Iraq and fought against the US invasion in 2003.
As rebel groups rallied against the regime of Bashar al-Assad in Syria in 2011, Al-Qahtani helped form Al-Qaeda affiliate Jabhat Al-Nusra - the group that would rebrand itself as HTS in 2018 and two years earlier formally cut ties with Al-Qaeda.
Al-Qahtani has been one of most vocal critics of Al-Qaeda in HTS, having led the group's efforts against the al-Qaeda-affiliated Hurras Al-Din group in Idlib.
Al-Qaeda supporters have accused Al-Qahtani of being a US collaborator, according Charles Lister, a senior fellow and director of the Syria and Countering Terrorism and Extremism programmes at the Middle East Institute.
Sources close to HTS told The New Arab's Arabic-language sister site, Al-Araby Al-Jadeed, that HTS member Abu Yazan Al-Dairi, an associate of Al-Qahtani, was arrested last Friday on charges of communicating with the US-led international coalition.
The sources indicated that Al-Qahtani's suspension is linked to information extracted from Al-Dairi.
In recent months, HTS has carried out a series of arrests and raids in Idlib in a bid to quash dissent and consolidate the group's domination in the last rebel-held pocket of Syria